Drug Database - Ginko

Common Names: ginkgo, Ginkgo biloba, fossil tree, maidenhair tree, Japanese silver apricot, baiguo, bai guo ye, kew tree, yinhsing (yin-hsing)

Latin Name: Ginkgo biloba

Classification: Herb

Ginkgo leaf extract has been used to treat a variety of ailments and conditions, including asthma, bronchitis, fatigue, and tinnitus (ringing or roaring sounds in the ears). Today, people use ginkgo leaf extracts hoping to improve memory; to treat or help prevent Alzheimer's disease and other types of dementia; to decrease intermittent claudication (leg pain caused by narrowing arteries); and to treat sexual dysfunction, multiple sclerosis, tinnitus, and other health conditions.

Ginkgo inhibits the action of platelets in the blood, thus interfering with blood coagulation. Don't use ginkgo if you are taking the blood thinner warfarin (Coumadin) or antiplatelet drugs such as clopidogrel (Plavix®). Ginkgo may lower blood sugar, so don't use it if you are already taking drugs for diabetes.

Numerous studies of ginkgo have been done for a variety of conditions. Some promising results have been seen for intermittent claudication, but larger, well-designed research studies are needed.

An NCCAM-funded study of the well-characterized ginkgo product, EGb-761, found it ineffective in lowering the overall incidence of dementia and Alzheimer's disease in the elderly. In this clinical trial, known as the Ginkgo Evaluation of Memory study, researchers recruited more than 3,000 volunteers age 75 and over who took 240 mg of ginkgo daily. Participants were followed for an average of approximately 6 years.

Some smaller studies for memory enhancement have had promising results, but a trial sponsored by the National Institute on Aging of more than 200 healthy adults over age 60 found that ginkgo taken for 6 weeks did not improve memory.

Other NCCAM-funded research includes studies on ginkgo for asthma, symptoms of multiple sclerosis, vascular function (intermittent claudication), cognitive decline, sexual dysfunction due to antidepressants, and insulin resistance. NCCAM is also looking at potential interactions between ginkgo and prescription drugs.

Side effects of ginkgo may include headache, nausea, gastrointestinal upset, diarrhea, dizziness, or allergic skin reactions. More severe allergic reactions have occasionally been reported.

There are some data to suggest that ginkgo can increase bleeding risk, so people who take anticoagulant drugs, have bleeding disorders, or have scheduled surgery or dental procedures should use caution and talk to a health care provider if using ginkgo.

Uncooked ginkgo seeds contain a chemical known as ginkgotoxin, which can cause seizures. Consuming large quantities of seeds over time can cause death. Ginkgo leaf and ginkgo leaf extracts appear to contain little ginkgotoxin.

Tell your health care providers about any complementary and alternative practices you use. Give them a full picture of what you do to manage your health. This will help ensure coordinated and safe care.

Ginkgo may alter the metabolism and effectiveness of some prescription and non-prescription medications. If you are being treated with any of the following medications, you should not use ginkgo without first talking to your health care provider:

Anticonvulsant Medications
High doses of ginkgo could decrease the effectiveness of anticonvulsant therapy, such as carbamazepine (Tegretol) or valproic acid (Depakote), in controlling seizures.

Antidepressant Medications
Taking ginkgo along with selective serotonin reuptake inhibitor (SSRIs) antidepressants including fluoxetin (Prozac), sertraline (Zoloft), paroxetine (Paxil), and escitalopram (Lexapro) -- may cause serotonin syndrome.

This condition is characterized by rigidity, tachycardia (fast heart rate), hyperthermia (high body temperature), restlessness, and diaphoresis (sweating). Ginkgo may enhance the effects (both good and bad) of antidepressant medications known as MAOIs, such as phenelzine (Nardil).

Antihypertensive Medications
Ginkgo may decrease blood pressure, so use of ginkgo along with prescription antihypertensive medications should be monitored by a health care provider. There has been a report of an interaction between ginkgo and nifedipine (Procardia), a calcium channel blocking drug used for blood pressure and arrhythmias.

Blood-Thinning Medications
Ginkgo has blood-thinning properties and therefore should not be used if you are taking anticoagulant (blood-thinning) medications, such as aspirin, clopidogrel (Plavix), dipyridamole (Persantine), heparin, ticlopidine (Ticlid), or warfarin (Coumadin). There has been bleeding in the brain reported when using a ginkgo product and ibuprofen (Advil), a non-steroidal antiinflammatory drug (NSAID).

Blood Sugar Lowering Medications
Ginkgo was reported to increase insulin levels in healthy subjects and to decrease insulin levels in diabetic patients. Use ginkgo supplements under the supervision of a health care provider if you are diabetic and taking insulin or oral blood sugar lowering drugs.

Cylosporine
Ginkgo biloba may help protect the cells of the body during treatment with the immunosuppressive (decreases immunity) drug cyclosporine.

Thiazide Diuretics
Although there has been one literature report of increased blood pressure associated with the use of ginkgo during treatment with thiazide diuretics, this interaction has not been verified by clinical trials. Nevertheless, you should consult with your health care provider before using ginkgo if you are taking thiazide diuretics.

Trazodone
There has been a report of an adverse interaction between ginkgo and trazodone (Desyrel), an antidepressant medication that resulted in an elderly patient going into a coma.